A conventional navigation apparatus applied, for example, to an automobile can be roughly classified into a route-guiding type apparatus and a non-route-guiding type apparatus.
The route-guiding type navigation apparatus displays information about an optimum route for reaching a destination on a screen of a display device. The optimum route for reaching the destination is automatically calculated by a computer accommodated in the navigation apparatus by inputting the present position and destination of the automobile before starting a journey. While travelling, a driver drives the automobile guided by information about the route displayed on the display screen until the automobile reaches the destination. Nevertheless, the conventional route-guiding type apparatus is impractical because of the difficulty related to the ability of the driver, errors of a locator and timing for indicating the route.
The non-route-guiding type navigational apparatus only displays a map as well as a present position, travelling locus, travelling direction and the like in the map on the screen of the display device and does not positively provide the driver with guiding information. Therefore, this navigation apparatus cannot achieve the original purpose of navigation.
As described above, the information presented by the non-route-guiding type navigational apparatus is less valuable to the driver. Further, the driver is prevented from paying attention to the forward direction of his automobile by observing the map on the screen while driving. Thus, a safety problem arises. On the other hand, information presented by the route-guiding type navigational apparatus forces the driver to travel along the designated route, thereby placing strong psychological stress on the driver and thus raises the possibility of causing danger. Further, according to present technology, since an instruction on the route is given to the driver without taking actual traffic conditions while travelling into consideration, a problem arises in that the navigational apparatus is less valuable when practically applied.
Taking the problems of the conventional navigation apparatus into consideration, an object of the present invention is to provide a practical and safe navigation apparatus and navigation method which can present valuable information to a driver without applying stress to him.